mod front_of_house {
    pub mod hosting {
        pub fn add_to_waitlist() {}
    }
}

// the keyword of use same as namespace with c++ in my option
use crate::front_of_house::hosting;

pub fn eat_at_restaurant(){
    hosting::add_to_waitlist();
}

mod customer {
    pub fn eat_at_restaurant(){
        super::hosting::add_to_waitlist();
    }
}

mod myCustomer {
    use super::front_of_house::hosting::add_to_waitlist;

    pub fn eat_at_restaurant () {
        add_to_waitlist();
    }
}